Just before Christmas, I saw the early-80s Boston hardcore band Mission of Burma in a Shoreditch cellar, playing to a crowd of young people barely born this century, typically too inarticulate to explain exactly what had led them to a room I expected to be peopled exclusively by nostalgic fortysomethings. Last week, I enjoyed Roscoe Mitchell, saxophonist of the 60s free-jazzers the Art Ensemble of Chicago, at another Dalston hangout, alongside 17-year-olds and septuagenarians. From where I am standing, the traditional demographics of music consumption seem to be dissolving. Although, admittedly, where I am standing is just by the gents' toilets in a succession of the hippest venues in western Europe.

CD reissues of unknown gems, and the internet-driven mass availability of everything instantly, mean pop culture's past is growing more rapidly than its present. Our sassiest sons and daughters are beyond our command, foraging far from whatever is drip-fed to them by broadcast media, and digging all manner of cross-generational guff. Your 12-year-old niece thinks that Searching for Sugar Man bloke, who had been working as a builder since 1971 until some hipster doofus put him in an arthouse documentary, is exactly the same as Bob Dylan because she discovered them both, for better or worse, on the same illegal download site, free of any illuminating cultural context or critical commentary.

I've spent this week listening to a new, commercially available, download of a previously unreleased 1975 album by a lost Chicago metal band called Medusa, rescued from mouldy master-tapes of the group's only session, found abandoned in the drummer's basement, where perhaps they should have stayed. I don't know if I really like First Step Beyond, but it's fascinating to my saturated palate because it shouldn't be here. First Step Beyond's decontextualised Neanderthal heaviness confuses itself and everyone who comes into contact with it, like a caveman in a Disney film who gets transported to 60s suburbia, takes a dump in Mom's Tupperware and wears her diaphragm as a hat. The fact remains, the instant availability of everything ever means I am consuming something that was never aimed at me, from a time and a place I have no connection with, and yet I am nearly enjoying it.

Not everyone is buying into the theory of the kaleidoscoping of culture. Last year I curated a selection of the 20 best standups working today for a show called The Alternative Comedy Experience. It aims to be an alternative to the more straightforward fare of shows such as Live at the Apollo, and is. I went for a meeting with the channel's marketing people, who had not watched any of the 12 episodes, but were principally, and understandably, concerned about how to sell this strange product to their target audience of 18- to 32-year-olds, whose loyalty to the channel encourages advertisers to fund it.

Identifying the youngest performers in the programme, marketing wondered if they could be profiled in info-outlets popular with 18- to 32-year-olds, their faces stamped on to hallucinogenic plant food tablets, or perhaps grafted on to the bodies of the stars of the pornographic films that all young people stream continuously to their mobile phones. When I was in a double act during the early 90s, when comedy was first the new rock'n'roll, our live audience was composed exclusively of children, which was a godsend, as the fact that their parents had to accompany them sometimes pushed our live crowds up into triple figures. Nonetheless I floated to marketing the idea that, in my more recent experience of comedy, the availability of clips of our show's quality turns on YouTube meant their audiences needn't, and didn't, follow delineated demographic lines. And I suggested that younger people might not necessarily be looking to consume product manufactured by content providers of solely their own age group. But talk soon moved on to the show's coruscating liberal satirist Paul Sinha's appearance on the daytime quiz show The Chase, and whether this could be a way of getting our programme profiled in Puzzler magazine.

Meanwhile, check me out! I've had my headphones on while writing this and I am coming round to First Step Beyond. Now I'm grooving my near 45-year-old ass around in my office chair to Medusa's nine-minute Transient Amplitude, which sounds like a thin no-budget Hawkwind with two bicycle lights replacing the psychedelic light show, and a dead frog on a string instead of a massive naked dancing woman. (Hawkwind, by the way, are a once-despised 70s group loved only by hippy grandads whom young people are now encouraged to admire as space-rock pioneers.)

Indeed, this Transient Amplitude growler makes me think these Medusa cats might be quite good after all. I don't know if I'm allowed to like them, but there doesn't seem to be anyone in any position of authority telling me I shouldn't, so I am going to anyway. The guitar is all over the place though, wandering randomly between the speaker channels, like marketing people searching for demographic certainties in an age where everything that ever was is suddenly available to everyone.